We’ve all been there. You’re feeling pretty chipper before you meet your friend for lunch – but within minutes, it’s clear that she’s not in a good mood. Perhaps she’s stressed about work, or her relationship is in trouble, or her shower is broken and her landlord won’t fix it. Whatever the reason, by the time you say goodbye, you’re feeling pretty bad-tempered yourself.

If you feel like you’re often susceptible to ‘catching’ your friends’ emotions (when they’re up, you’re up; when they’re down, you’re down), you’re not alone. According to a new study by researchers at the University of Warwick, both good and bad moods are prone to ‘spreading’ across friendship networks like emotional infections.

The team analysed data from a major study of US teenagers for the study, published recently in the journal Royal Society Open Science. They found that people with more friends who suffered from bad moods were more likely to experience low moods themselves, and were less likely to feel happier over time.

In contrast, adolescents with more positive social circles – that is, friends who were generally happy – were more likely to feel upbeat, and less at risk of feeling low.

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While the impact of friends’ low moods was significant, it wasn’t strong enough to push other friends into actual depression. However, the researchers did find that a negative friendship circle could increase the risk of someone experiencing “depressive symptoms” just below those needed for a clinical diagnosis.

“Evidence suggests mood may spread from person to person via a process known as social contagion,” said public health statistics research Rob Eyre, who led the study.

He added that previous studies have found that “social support and befriending” can help prevent or reduce the effects of mood disorders, and that “recent experiments suggest that an individual’s emotional state can be affected by exposure to the emotional expressions of social contacts”.

Professor Frances Griffiths of Warwick Medical School was a co-author on the paper. She said that the results could have implications for how we think about depression, low moods and friendship.

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“Understanding that these components of mood can spread socially suggests that while the primary target of social interventions should be to increase friendships because of its benefits in reducing the risk of depression, a secondary aim could be to reduce spreading of negative mood,” she said.

The study confirms the importance of spending time with people who lift us up, rather than those who drag us down. That doesn’t mean you should demand your friends bring nothing but sunshine and sparkle into your life at all times: we all have bad days, and part of being a good friend means supporting one another through rocky patches. (And of course, if a friend is suffering from mental health issues, it’s important to be as compassionate and present as possible.)

But if your mate is just a habitual moaner who can’t resist pointing out the raincloud beneath every silver lining, you might want to cut down on the time you spend together – lest you catch their bad mood.

Images: Omar Lopez / Rex Features